The present invention relates to a method and apparatus for applying adhesive film to an article.
Decorative films are used in the manufacture of vehicles and other consumer products to provide a second xe2x80x9cpaintxe2x80x9d color, product identification, product operation instructions, or control panel indicia. By using decorative films, multiple decorative painting processes can be eliminated while providing high quality and durable graphics. Generally, decorative films are manually applied. Adhesive protective layers must be removed from the decorative film and the film must be carefully and evenly applied without wrinkles or misalignment. Considerable skill may be required to apply a relative large section of film to an article because while one end of the film is being applied the other end must be held away from the article so that inadvertent contact of the film adhesive does not cause the film to be applied improperly.
In the manufacture of vehicles decorative films have increasingly been used to provide decoration without additional paint processing operations. Sport utility vehicles, mini-vans and other vehicles use adhesive film to cover portions of body panels between windows to create a continuous wrap around window appearance. Generally, glossy black film is applied to door frames or body pillar surfaces that are visible from the exterior of the vehicle. Due to problems encountered in applying film on an assembly line it had been proposed to provide molded plastic trim pieces instead of film to cover body parts between windows. The use of molded plastic trim pieces adds weight and unnecessarily increases costs.
Decorative films are applied in automotive manufacturing facilities after the vehicle painting operations are completed but before installation of window trim and assembly of window and door seals. It may take as many as three or four workers to apply film to both sides of the vehicle. The prior art method of applying decorative film to a door frame was accomplished by several workers using a simple fixture to hold the film over the location where it is to be applied. Workers then work with a brush or other wiping tool to smooth the adhesive film onto the article. One problem with this approach is variability in locating the film on the article and a tendency of the film to adhere in the wrong location causing wrinkles in the finished product. If the film is misapplied or is applied with wrinkles, it is necessary to remove the film and apply another section of film. To do so, window trim, window seals, and door seals must be removed and reassembled.
Automotive manufacturers use decorative film (or tape) to pin stripe, apply a model name or brand designation or for a special xe2x80x9cpaintxe2x80x9d details on limited edition models, and the like. An effective, repeatable process and fixture for applying such decorative media to a vehicle is needed. In addition, a method and fixture for applying control panel decoration for washers, dryers, and other consumer products is needed. These and other problems and obstacles to prior art methods and devices are addressed by applicant""s invention as summarized below.
It is a principal object of the present invention to provide a simple and effective method and apparatus for applying film, tape xe2x80x9cchromexe2x80x9d trim pieces, plastic guards and other pressure sensitive adhesive bearing media to articles. To be acceptable, the method and apparatus must be capable of applying films, tapes and other pressure sensitive adhesive applied media with high standards of repeatability and a minimal scrap rate.
According to the invention, an apparatus is provided for applying an adhesive film to an article. The apparatus includes a fixture on which at least one clamp is mounted for temporarily securing the fixture to the article at a predetermined location on the article. First and second film locator clips are mounted on the fixture and the adhesive film is attached to the film locator clips. At least one of the film locator clips is biased in one direction to apply tensioning force to the film to initially hold at least part of the film in a spaced relationship to the article. A wiping head is mounted for movement relative to the fixture and is shifted to engage the film and cause one portion of the film to be applied to the article. The wiping head then moves from that one portion of the film to another portion of the film to apply the other portion of the film to the article.
According to the invention the article may be a vehicle and a plurality of clamps may be provided that engage at least two structural edges of a body part of the vehicle to locate the fixture relative to the body part prior to applying film to the vehicle. For example, the body part may be a vehicle door and the plurality of clamps may be arranged in two sets with one set of claims engaging the B pillar of the door and the other set of clamps engaging in the top and bottom sills of a window opening formed in the door.
According to other aspects of the invention relating to the film locator clips, one of the film locator clips may be used to hold the first part of the film stationary as the film is applied to the vehicle. The second film locator clip is then movable in response to the wiping head moving from one portion of the film to another portion of the film while the second film locator clip holds a second part of the film. The second film locator clip, if movable, may use at least one air pressure biasing member and a source of air pressure that provides the biasing force. The air pressure biasing member may be a pair of piston pins disposed within a housing having a pair of bores that partially receive the pair of piston pins.
The wiping head made according to the present invention may be mounted on a carriage. The carriage moves along a track aligned with the direction that the carriage moves on the track. The wiping head may be secured to a cylinder drive mechanism that shifts the wiping head to engage the film and press the film in to engagement with the vehicle. The wiping head is generally moved normal to the surface of the vehicle to which the film is applied.
According to the method of the present invention, decorative film having a adhesive coating on one side is applied to an article in a predetermined location on a surface. The steps of the method include locating the fixture, such as the fixture described above, on the article. A film segment is attached to first and second clips at spaced locations. A biasing force is applied to the film segment that causes tension to be applied to the film by the first and second clips for the purpose of preventing the film from sagging toward the article. A wiper is moved in a first direction into the film to cause a first portion of the film to contact the article and cause the adhesive to adhere the first portion of the film to the article. The wiper is then moved in a second direction along the film segment to cause additional portions of the film to progressively contact the article and cause the adhesive to adhere additional of portions of film to the article.
According to the invention as it relates to the application of a biasing force to the film segment, the biasing force may be provided by a second clip that applies a dynamic force on the segment by pulling on one end of the film segment. The step of applying a biasing force may be performed by providing a slide that moves the second clip. The slide is preferably attached to a track that is attached to the fixture. Alternatively, the biasing force could be applied by a rotatable member. The biasing force may be developed by either a air spring or a solid spring element operating between the track and the slide.
The present invention also relates to the clamping mechanism for locating the fixture on the article. Generally, opposed clamping members are used to locate the fixture on an article. The clamping members clamp the fixture to the article in alignment with a reference line on the article that defines the predetermined location where the film is to be applied. Solid clamps, vacuum cups or other clamping apparatus can be used in accordance with the invention.
According to another aspect of the invention the wiper that applies the film to the article is moved in a first direction by means of a linear motor mounted on the fixture that advances and retracts relative to the film. The linear motor may incorporate an air cylinder, a hydraulic cylinder or a rack and pinon gear set.
According to another aspect of the method of the present invention, the film is held between the first and second clips and is initially bent into an oblique angular orientation when the wiper initially causes the film to contact the article. The wiper establishes a line of contact between the article and the film. As the wiper moves toward the second clip and away from the first clip to cause additional portions of the film to adhere to the article, the wiper maintains a line of contact with the article. The angle of the unapplied film at the line of contact relative to the surface increases as the wiper advances in the second direction.
The above aspects and advantages of the present invention are described more specifically with reference to the attached drawings of the invention and is described in detail below.